Eccentric pulley drive



Se t. 20, 1966 K. M. ALLEN ET AL 3,273,698

ECCENTRIC PULLEY DRIVE Filed June 1, 1964 FIG. I I2 KENNETH M ALLEN CHESTER H. HARPER INVENTORS.

BUG/(HORN, BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS United States Patent ()fiice 3,273,698 Patented Sept. 20, 1966 3,273,698 ECCENTRIC PULLEY DRIVE Kenneth M. Allen and Chester H. Harper, Newberg, reg., assignors to Allen-Harper, Inc., Newberg, 0reg., a corporation of Oregon Filed June 1, 1964, Ser. No. 371,289 Claims. (Cl. 198-220) This invention relates to an improved eccentric pulley drive, and more particularly to an adjustable eccentric pulley drive for a vibrating conveyor.

An object of the invention is to provide a new and improved eccentric pulley drive.

Another object of the invention is to provide an adjustable eccentric pulley drive for a vibrating conveyor.

A further object of the invention is to provide a simple, effective adjustable eccentric pulley drive for a vibrating conveyor adjustable between no movement of the conveyor and maximum movement of the conveyor.

Still another object of the invention is to provide a simple eccentric pulley drive for a vibrating conveyor acting both as a clutch and a drive.

The invention provides an eccentric pulley drive having a drive pulley, a driven pulley mounted resiliently or a conveyor bed, a belt extending partially around and between the pulleys and an eccentric pulley adjustable laterally relative to one of the courses of the belt between a retracted position in which the eccentric pulley does not deflect the belt and a second position in which the eccentric pulley is driven by the belt and deflects the belt as it is rotated to move the driven pulley toward and away from the drive pulley to reciprocate the conveyor bed. Preferably the eccentric pulley is positioned substantially nearer one of the drive and driven pulleys than the other so that, by adjusting the position of the eccentric pulley relative to the belt, the deflection of the belt is changed and the throw of the drive is changed.

A complete understanding of the invention may be obtained from the following detailed description of an improved eccentric pulley drive forming a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

FIG. 1 is a partially sectional, side elevation view of an eccentric pulley drive forming one embodiment of the invention; and

FIG. 2 is a horizontal sectional view of the eccentric pulley drive of FIG. 1.

Referring now in detail to the drawings, an eccentric pulley drive 10 serves to vibrate a conveyor trough or bed 12 mounted by resilient, strap-like struts 14 on a combined base and housing 16. The trough 12, struts and base form a parallelogram permitting oscillation of the trough relative to the base to the right and left, as viewed in FIG. 1, but preventing any substantial horizontal movement of the trough that is transverse to the trough. Movement of the trough downwardly and to the left as viewed in FIG. 1 is resisted by the struts. The base 16 may be mounted directly on the floor or may be mounted floatingly or resiliently as is well known in the vibrating conveyor art. The drive 10 includes an electric motor 26 enclosed in and fixed to the base and driving by its shaft 28 centric drive pulley 30, a belt 32 and centric driven pulley 33 carried by pin 34 journaled in bearings 36 carried by a clevis 38 connected to the bottom of the conveyor trough by a strong tension spring 40 fixed to bracket 42 which is rigid on the conveyor trough. A rigid pin 44 fixed rigidly to the clevis 38 extends through parallel guide slots 46 in parallel plates 48 fixed rigidly to the bottom of the conveyor bed and bracketing the clevis. The plates 48 and the slots 46 extend longitudinally of the conveyor trough. The spring 40 keeps the belt 32 always under tension.

An eccentric pulley 50 is mounted by bearing 52 rotatably on shaft 54 carried eccentrically by disc 56, which is mounted rotatably on the shaft 28 by bearing 58. The disc 56 has an actuating arm 60 rigid therewith and connected by a pivot connection 62 to a piston rod 64 of a servo device 66 including cylinder 68 mounted pivotally by pin 70 on bracket 72 fixed to the base 16. The servo device includes a follower rod 74 fixed to the piston JOd 64 and to a valve 76 controlling the supply and exhaust of fluid to and from the cylinder 68 through flexible conduits 78 and 80. Supply and exhaust conduits 82 and 84 are connected to the-valve 76 and an adjusting rod 86 is controlled by manually operable handle 88 pivotally mounted on the base 16. By moving the handle 88 manually, the valve 76 is actuated to supply additional fluid under pressure to one end of the cylinder 68 to move the piston rod to a more extended or a more contracted position relative to the cylinder until the follower rod 74 moves the valve 76 to a closed position and the piston rod is held in its adjusted position. Adjustment of the piston rod moves the disc 56 either clockwise or counterclockwise, as viewed in FIG. 2. When the disc is moved clockwise, the eccentric pulley 50 moves to increase the deflection of the course of the belt 32 engaged thereby. Movement of the disc 56 counterclockwise lessens the deflection of the engaged course of the belt, and the disc may be moved to an extreme retracted position in which the pulley 50 is not in driven engagement with the belt 32. A screw 90 threaded into a tapped bore in the top of the base 16 projects through arcuate slot 92 in the disc 56 and may be tightened to hold the disc 56 in a desired adjusted position on the base 16. The disc 56 mounts the eccentric pulley 50 quite close to the drive pulley 30 and quite far from the driven pulley 33. The eccentric pulley has suitable means as illustrated by hole 94 in the longer radius portion thereof for balancing it from the weight standpoint.

In the operation of the above-described vibrating conveyor, when the disc 56 is in a retracted position holding the eccentric pulley 50 in its retracted position in which its lowest point is not in engagement with the belt 32, no motion is imparted to the conveyor trough 12. However, when the servo device 66 is actuated to adjust the disc 56 clockwise from its retracted position to any position in its operating range in which the eccentric pulley drivingly engages the course of the belt adjacent thereto and thereby deflects the belt, the eccentric pulley is rotated rapidly by the belt and deflects the course of the belt engaged thereby from minimum deflection to maximum deflection, the difference or throw being equal to the eccentricity of the pulley 50, and return once for each revolution of the eccentric pulley. As the deflection of the belt 32 is increased and lessened, the pulley 33 and clevis 38 are correspondingly pulled toward or permitted to move away from the pulley 30 and the conveyor trough 12 is moved to the left and right by the resulting variation in the pull of the spring 49 thereon and advances material on the trough to the right. The throw imparted to the pulley 33 and conveyor trough is increased by adjusting the disc 56 further in a clockwise direction as viewed in FIG. 2 to increase the average deflection of the adjacent course of the belt 32 by the pulley 50, and this throw is lessened as desired by adjusting the disc 56 in a counterclockwise direction.

The motor 26 is preferably operated at a constant speed sufliciently high to provide the frequency of vibration desired which, of course, is equal to the rate of rotation of the eccentric pulley 50 by the belt 32. This frequency may be above the resonant frequency of the conveyor, and the vibration of the conveyor is brought immediately up from zero to the operating frequency by the clutch action operable as the eccentric pulley is moved from its retracted position into its operating range of positions.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the inventioin. Numeous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. In combination,

a conveyor bed mounted for back-and-forth movement,

a driven pulley connected to the conveyor bed,

a drive pulley rotated continuously,

an endless belt extending around and between the pulleys in a tensioned condition,

an eccentric pulley,

and adjustable means carrying the eccentric pulley for moving the eccentric pulley from a retracted position out of driven engagement with the belt to an operating position deflecting a course of the belt and driven by the belt.

2. In combination,

a base a conveyor bed mounted for back-and-forth movement relative to the base,

a continuously rotated centric drive pulley mounted on the base,

a centric driven pulley mounted on the conveyor bed,

an endless belt coursing on the drive and driven pulleys and extending under tension therebetween,

and an eccentric punlley on the base in a position drivingly engaging and deflecting one course of the belt and driven by the belt to pull the driven pulley and the conveyor bed toward the drive pulley once for each revolution thereof.

3. In combination,

a conveyor bed,

a base,

biasing means mounting the conveyor bed for back-andforth movement relative to the base and biasing the conveyor bed in one direction relative to the base,

a centric driven pulley carried by the conveyor bed,

a centric drive pulley carried by the base and rotated continuously,

an endless belt mounted on and extending between the drive and driven pulleys and limiting movement of the conveyor bed in said one direction,

an eccentric pulley,

and a mount on the base holding the eccentric pulley in a position in which the periphery thereof engages the outer face of a course of the belt extending between the drive and driven pulleys and deflects said one course of the belt toward the other course thereof.

4. The combination of claim 3 wherein the mount is adjustable to move the eccentric pulley to adjust the average deflection of said one course of the belt by the eccentric pulley and holds the eccentric pulley substantially nearer to one of the drive and driven pulleys than to the other,

and means for adjusting the mount.

5. In combination,

a driven pulley,

a clevis mounting the driven pulley,

a conveyor bed,

guide means mounting the clevis slidably on the conveyor bed,

a base,

a drive pulley on the base and rotated continuously,

spring means engaging the clevis and the conveyor bed and urging the driven pulley away from the drive pulley,

an endless belt coursing on the pulleys,

and eccentric means driven by the belt.

6. In combination,

a conveyor bed,

a guide secured to the bottom of the conveyor bed and extending therealong,

a clevis mounted slidably in the guide,

a tension spring connecting the clevis to the conveyor bed,

a base,

means mounting the conveyor bed for movement relative to the base,

a drive pulley carried by the base,

a driven pulley carried by the clevis,

an endless belt mounted on the drive and driven pulleys,

and eccentric means for varyingly deflecting the belt.

7. In combination,

a base,

an electric motor mounted on the base and having a shaft,

a drive pulley keyed to the shaft,

a conveyor bed,

strut means mounting the conveyor bed movably relative to the base,

a driven pulley carried by the conveyor bed,

an endless belt mounted on the drive and driven pulleys,

an adjustment member mounted pivotally on the shaft,

an eccentric pulley mounted on the adjustment member,

and means for moving the adjustment member to move the eccentric pulley into driven and deflecting engagement with one course of the belt to a point thereon near to the drive pulley and far from the driven pulley.

8. The combination of claim 7 wherein the adjustment member comprises a disc mounted axially on the shaft and mounting the eccentric pulley eccentrically thereon,

the means for moving the adjustment member comprising means for turning the disc on the shaft to a selected position and holding the disc in said selected position.

9. In combination,

a fixed member,

a conveyor bed mounted for back-and-forth movement relative to the fixed member,

strand means under tension connecting the fixed memher the and conveyor bed,

resilient means urging the conveyor bed in a direction tensioning the strand means,

eccentric pulley means,

means for rotating the eccentric pulley means,

and adjustable means carrying the eccentric pulley means for moving the eccentric pulley means from a retracted position out of engagement with the belt to an operating position deflecting the strand means.

10. In combination,

a base,

a conveyor bed mounted for back-and-forth movement relative to the base,

a first centric pulley mounted on the base,

a second centric pulley mounted on the conveyor bed,

an endless belt coursing on the centric pulleys,

means urging the conveyor bed in a direction tensioning the belt,

an eccentric pulley on the base movable to an operative position drivingly engaging and deflecting one course of the belt and a retracted position out of driving engagement with the belt,

and means for rotating one of the eccentric pulley and the first centric pulley.

References Cited by the Examiner UNITED STATES PATENTS 1,596,465 8/ 1926 Stebbins.

EVON C. BLUNK, Primary Examiner.

RICHARD E. AEGERTER, Examiner. 

1. IN COMBINATION, A CONVEYOR BED MOUNTED FOR BACK-AND-FORTH MOVEMENT, A DRIVEN PULLEY CONNECTED TO THE CONVEYOR BED, A DRIVE PULLEY ROTATED CONTINUOUSLY, AN ENDLESS BELT EXTENDING AROUND AND BETWEEN THE PULLEYS IN A TENSIONED CONDITION, AN ECCENTRIC PULLEY, AND ADJUSTABLE MEANS CARRYING THE ECCENTRIC PULLEY FOR MOVING THE ECCENTRIC PULLEY FROM A RETRACTED POSITION OUT OF DRIVEN ENGAGEMENT WITH THE BELT TO AN OPERATING POSITION DEFLECTING A COURSE OF THE BELT AND DRIVEN BY THE BELT. 